giggle vs piss one's pants

giggle

verb
  • To laugh gently in a playful, nervous, or affected manner. 

noun
  • Fun; an amusing episode. 

  • A high-pitched, silly laugh. 

piss one's pants

verb
  • To laugh uncontrollably. 

  • To be extremely frightened. 

  • To wet oneself; to urinate in one's own clothes while they are being worn. 

How often have the words giggle and piss one's pants occurred in a corpus of books? (source: Google Ngram Viewer )